vertebral column
The main distinguishing feature of vertebrates is their vertebral column, or backbone see Figure below . The backbone runs from the head to the tail along the dorsal top side of the body. The vertebral column is the core of the endoskeleton. It allows a vertebrate to hold its shape. It also houses and protects the spinal nerve cord that passes through it. The vertebral column is made up of repeating units called vertebrae singular, vertebra . In many species, there are shock-absorbing discs between the vertebrae to cushion them during movement.